- Patients with the potential for pregnancy or impregnating their partners must agree to follow acceptable birth control methods to avoid conception. The effects of bevacizumab on the developing human fetus are unknown. For this reason, women of child-bearing potential and men must agree to use adequate contraception (double barrier method of birth control or abstinence prior to study entry, for the duration of study participation and after completing treatment. Should a woman become pregnant or suspect that she is pregnant while she or her partner is participating in this study, she should inform the treating physician immediately.